1. Field of the Invention
The present invention relates to round balers and other baling equipment. More particularly, the invention relates to a bale shape monitor for round balers that assists an operator in forming uniform bales of crop.
2. Description of the Prior Art
Conventional round balers pick-up crop from a windrow and form it into compacted bales in a bale forming chamber. When a bale reaches a desired size and/or shape, sensors signal a controller that subsequently sends a signal to an operator's panel to instruct the operator to stop forward motion of the baler so that a bale wrapping operation can be performed. Once a bale has been formed and wrapped, it is ejected from the baler so a new bale can be formed and wrapped.
In most instances, the crop windrow picked up by a round baler tends to be narrower than the overall length of the baling chamber. The baler must consequently be steered left and right as it pulled across the field so an equal amount of crop material is delivered along the length of the chamber during the bale cycle; otherwise, the baler will likely form an asymmetrical bale having an uneven diameter from end to end. For example, if the baler is positioned relative to the windrow so that a disproportionate amount of crop is delivered to the left end of the baling chamber, the bale will likely have a conical shape, with the left end of the bale having a greater diameter and density than the right end. Nonuniform bale formation results in unsightly bales that are difficult to sell, stack and tie. Moreover, nonuniform bale formation often damages or places undue wear on the bale forming components.
Even the most skilled baler operator has difficultly in tediously weaving the baler from side to side for ensuring even delivery of crop material between the sidewalls of the baler. Accordingly, bale shape monitors have been developed to assist the operator with uniform bale formation. Conventional bale shape monitors typically include indicators placed within the cab of the tractor to signal to the operator when the bale is not being properly shaped. Traditional indicators include bale shape displays which represent the shape of the bale from end-to-end or at certain locations along the length of the bale. Some indicators also include “driving lights” which signal to the operator when to steer left, steer right or simply drive forward. Additionally, some balers have been equipped with a steering mechanism for automatically steering the baler left and right in response to the bale shape sensed by the monitor.
The indicators mentioned above are traditionally operated by one or more sensors on the baler. In round balers having an expandable baling chamber defined in part by a plurality of endless belts, the sensors are often associated with the endless belts adjacent the sidewalls of the baler. Each end sensor is often positioned along a stretch of the corresponding belt to detect when the stretch becomes slackened or tightened. The belts are traditionally tensioned by a single slack takeup mechanism, and accordingly, slackening of one of the belts relative to the remaining belts indicates that the area of the baling chamber bound by the one belt is receiving less crop material than the others. Alternatively, the end sensors are positioned along stretches of the belts defining the baling chamber so as to directly sense the diameter of the bale. The operator may consequently steer the baler left or right depending upon the diameter of the bale sensed adjacent the ends thereof.
Known bale shape monitors suffer from several limitations. For example, existing bale shape monitors have indicators that are too sensitive to non-uniform bales when the bales are relatively small and aren't sensitive enough when the bales are almost fully formed. This is because it takes a smaller amount of crop to change the shape of a bale when the bale is small and a much larger amount of crop to change the shape when the bale is nearly fully formed. The indicators therefore “jump around” when the bale is small, because a small amount of crop can quickly make one end of the bale relatively larger than the other end, causing the bale shape indicators to change rapidly and thus prompting the operator to needlessly weave the baler back and forth at a high frequency. Just as seriously, the indicators don't signal an uneven bale quickly enough when the bale is nearly fully formed, causing many bales to reach full size before the operator can make necessary driving adjustments.
Known bale shape monitors also typically present information about uneven bales in black and white text and/or graphs that fail to get the operator's attention quickly enough.
Accordingly, there is a need for an improved bale shape monitor that overcomes the limitations of the prior art.